1. Field of the Invention
The present invention relates to continuous passive motion devices for the rehabilitative and therapeutic mobilization of human synovial joint and surrounding soft tissue, and more particularly, the invention relates to continuous passive motion devices for upper extremity forearm therapy.
2. History of the Related Art
In recent years it has become evident that the rehabilitation and treatment of injured joints and surrounding soft tissue can be expedited by use of continuous passive motion (CPM) applied to the involved joint. CPM entails moving the joint via its related limbs through a passive controlled range of motion without requiring any muscle coordination. Active motion is also beneficial to the injured joint, however, muscle fatigue limits the length of time the patient can maintain motion therefore a device that provides continuous passive motion to the joint is essential to maximize recovery. Numerous studies have proven the clinical efficacy of CPM to accelerate healing and maintain range of motion.
Furthermore, the rehabilitation of joints and soft tissue through CPM has become an important modality in the treatment of articular injuries. The need for a CPM device specific to the forearm is justified by the complications in the recovery process of distal radial fractures and fractures to the wrist. The wrist is one of the most frequently fractured bones in the human body. Present protocols for wrist fracture treatment require the wrist to be immobilized with the result that the muscles that provide the forearm with the ability to pronate and supinate contract. This effectively limits the ability of the forearm to move through its natural range of motion. The ability of the forearm to pronate and supinate is essential in maintaining a normal functional lifestyle. Without this range of motion the patient's ability to undertake routine daily activities such as turning a door knob, turning a key, eating with utensils may be severely compromised.
U.S. Pat. No. 5,503,619 issued to Bonutti discloses an orthosis device for bending of wrists in extension and flexion. This patent does not provide for pronation or supination of the wrist joint. Similarly, U.S. Pat. No. 5,067,479 issued to Saringer et al. is directed to a device for continuous passive motion of the wrist joint in flexion and extension.
U.S. Pat. No. 4,899,735 issued to Townsend et al. is directed to a torsion bar splint for pronation and supination of the wrist and forearm. This device is an active exercise device which includes a pair of telescoping rods with the a bracket pivotally attached at one end of a first rod for limited pivotal movement about the longitudinal axis of the first rod, the bracket being adapted to be secured to the palm of the hand by a plaster cast. The opposing end of the second rod engages a one-way clutch attached to a bracket adapted to be affixed to the user's upper arm thereby locking the arm in 90.degree.. The two telescoping rods are locked together to prevent rotation with respect to each other by a locking screw and the user actively exercises the distal radioulnar joint by rotating the wrist in the direction allowed by the one-way clutch thereby pronating or supinating the wrist. The one-way clutch retains the wrist in the furthest extent of its range of motion and to release the joint to return to its relaxed position requires the user to loosen the locking screw to allow rotation of one rod with respect to the other rod. This type of device is awkward to fit into, is an active exercise device only, and requires constant readjustment by the user.
Therefore, it would be very advantageous to provide a CPM device for the forearm which provides for an adjustable range of motion during therapeutic exercise.